Master Thesis Defense by Maiken Kristiansen Revheim

Title: Greenland Ice Sheet Surface Water Vapour Fluxes from Automatic Weather Station Records. - A Study of Greenland Ice Sheet Surface Water Vapour Fluxes in a Changing Climate

The Greenland ice sheet’s mass loss, primarily driven by surface melting and ice discharge, has gained attention in recent decades due to its implications for future sea level rise. However, the role of surface water vapour flux (SWVF) in this mass loss has received comparatively less study. Understanding the response of SWVF to climate change is crucial for accurately assessing the ice sheet’s future. This research builds upon Box and Steffen (2001), who estimated the net SWVF of the ice sheet using Greenland Climate Network (GC-Net) automatic weather stations (AWSs) data from 1995 to 2000. Here, their work is extended by incorporating GC-Net AWS data up to 2022 and including data from the PROMICE AWS network. The aim is to investigate how water vapour fluxes are influenced by Arctic warming.

Using various interpolation methods such as 3D universal kriging and trend surface mapping with in situ data, the yearly average mass loss by SWVF is estimated to be between 44 Gt and 51 Gt, with uncertainty estimates ranging from 10 Gt to 37 Gt. Here, it is estimated that each degree Celsius of temperature increase will lead to a 5 Gt increase in yearly mass loss. Additionally, the spatial and seasonal patterns in SWVF are investigated. The accuracy and reliability of the regional climate model RACMO2.3p2 in estimating SWVF are evaluated and a bias correction is implemented to enhance its predictive capabilities. The limitations of the methods employed are presented and discussed.

Supervisors: Christine S. Hvidberg (NBI), Jason Box (GEUS)
Censor: Peter Aakjær